ICP 40VA 120V to 24V Transformer for SUP20M2401BIA — OEM L01F009 | Ships Today

Overview

This OEM kit covers the L01F009 control transformer (TRANS 120>24 40VA) and the L01H009 24VAC relay (AG90-23242-024W) for the ICP / Tempstar / Heil SUP20M2401BIA. The transformer steps 120-volt line power down to 24 volts at 40VA to power the thermostat, control board, and relay circuit, while the relay switches a line-voltage load on command from that 24V circuit. A failed transformer leaves the entire low-voltage system dead — no thermostat response and a blank control board — while a failed relay causes mis-sequencing or stuck loads. Replacing with exact OEM parts restores correct control voltage and switching.

Specifications

Compatibility

Designed for the ICP-family SUP20M2401BIA and shared across many ICP, Tempstar, Heil, and Comfortmaker units running a 120V primary / 24V 40VA control circuit. Confirm your primary voltage is 120V before ordering.

Installation Guide

1. Safety First — Disconnect power at the breaker and verify zero voltage with a multimeter.
2. Access — Remove the service / control panel to reach the transformer and relay.
3. Document — Photograph all primary, secondary, and relay wiring before disconnecting.
4. Remove — Label and disconnect leads, then unfasten the failed transformer and relay.
5. Install — Mount the new L01F009 and L01H009 and reconnect each wire per your photo.
6. Test — Restore power and confirm 24VAC at the secondary and proper relay pull-in.

Signs You Need a Replacement

• No 24V control power; blank board and unresponsive thermostat.
• Repeatedly blown low-voltage fuse.
• Overheated, buzzing, or burnt-smelling transformer.
• Relay chatter or a load that stays on or won't start.

Shipping & Returns

Ships same day before 3 PM CST. 30-day returns. Backed by the National HVAC Parts fitment guarantee.